The present invention relates to a termite shielding structure for preventing termites from entering from underground into underfloor portions of a building, and particularly to a termite shielding structure and a method for constructing the same that is capable of preventing termite paths from being formed around piping piercing through underground beams of mat foundations in case a foundation for the building is formed of mat foundations of reinforced concrete.
In case ventilation of an underfloor portion in a building is poor, it is often the case that the building is eroded by termites. Termites favorably breed on temperate and humid soil, and by entering an underfloor portion from cracks in foundations or peripheries of underground piping, they erode buildings.
Thus, measures are usually taken in that termite shielding chemicals (repellents or insecticides) are dispersed on soil on underfloor portions of buildings to prevent termites from entering owing to their chemical efficacy. However, chemical efficacy of termite shielding chemicals vanish after a short term and when used in a large amount, these chemicals may pollute peripheral environments of the building or do harm to residents, persons performing the dispersion or any other creatures.
In case foundations of the building are mat foundations of reinforced concrete and outer peripheral portions of the building are surrounded by underground beams of these mat foundations, it is possible to prevent termites from entering at least in a range of several tens of centimeters from the ground surface by the use of these underground beams of reinforced concrete. However, in case piping for plumbing water, gas or others as well as guiding pipes for electric wiring cables that are embedded underground are arranged to pierce through underground beams, there still exists the danger that termite paths be formed in the periphery of these piping.
Thus, such problems are generally coped with by preliminarily embedding tubular sleeves into the underground beams at the time of installing concrete for the underground beams wherein these sleeves form hole portions for piping piercing through the underground beams, and after inserting piping such as steel pipes that are directly used for delivery of plumbing water or other fluids or vinyl chloride pipes that serve as guiding pipes for electric wiring cables, mortar is filled into clearances formed between inner peripheral surfaces of the hole portions and pipes for preventing the entry of termites.
However, in such a termite shielding structure, these operations of filling mortar into clearances formed between hole portions for the piping that are formed by the sleeves and pipes are troublesome and result in higher construction costs, and it was often the case that the filling of mortar into the hole portion interior was incomplete so that there was still a path left for the termites to enter.